BLOOD BUFFERS: a program to simulate blood pH The model here presented has three parameters: arterial pH, arterial PCO2 and the overall buffer capacity of arterial blood. It calculates the changes in pH and buffer capacity induced by respiratory changes in PCO2; for example, if an estimate of the venous PCO2 is provided, it calculates the arterio-venous pH difference and total CO2 difference. A detailed explanation of the model is provided below. arterial blood pH (suggested value: 7.4) arterial PCO2 (in mmHg; suggested value: 38) venous PCO2 (in mmHg; suggested value: 45) overall buffer capacity (suggested value: 38 mEq/L) Should I explain the model? no yes